Enermax Liberty ELT500AWT cold boot automatic shut off [HEAT appears to solve issue]
Hello all, and happy holidays,
First I will state my question: What do you think is causing the power supply to automatically shut down when cold? (somewhere <65F) After I heat it up for a few minutes using a space heater, it works on the first try! It would be nice to not have to heat it up using a space heater before starting it up. Kind of amusing though.
Here are my observations:
Related threads (to this PSU model):
Perhaps the heat sink sensor is faulty? There is no documented under temperature protection. Perhaps the cold temperature causes a voltage/current measurement to be out of bounds so the PSU shuts off? I have a cheap multimeter here, but it only updates at 2Hz. Everything appears to be in order once the computer boots. If desired I could go to work and grab some nice 1000+Hz curves depicting various properties of the cold/warm PSU startup. I could also take some photos of the guts of the PSU.
In post#14 of that last thread I pointed to: https://www.badcaps.net/forum/showpo...1&postcount=14 Mad_Professor links to pdfs containing characteristics of components in the PSU plotted against temperature (it seems as temperature decreases, things discharge faster [due to decreasing resistance], and I can't tell how voltage changes as theres a lot of terminology in those that I'm not familiar with). Seems plausible that it is just too cold I suppose. To anyone else who has a PSU that won't startup, try heating it up using a space heater?
Just wondering if anyone had any thoughts or suggestions.
First I will state my question: What do you think is causing the power supply to automatically shut down when cold? (somewhere <65F) After I heat it up for a few minutes using a space heater, it works on the first try! It would be nice to not have to heat it up using a space heater before starting it up. Kind of amusing though.
Here are my observations:
- I've had this PSU for 5+ years. Dual rail. Couple HDDs, AMD CPU 125W, graphics card recommends 400W PSU w/ 12V current rating of 26A, but this PSU's relevant rating is 22A for each rail w/ 32A combined: http://images10.newegg.com/NeweggIma...194-003-09.jpg Gaming works great, so I don't think there is an issue here.
- A couple months ago I've needed to press the startup button once or twice instead of just once. As time increased (and the room temperature decreased due to winter), I've occasionally needed to press the startup button more times in sequence. Most recently it takes 20+ times without heat added (room temp is chilly, around 58F I guess).
- Rebooting always works.
- Cold booting works w/i 20 minutes or so of shutting it down (I suspect due to lingering heat).
- When cold, my power supply seems to shut off a split second after I press the desktop power button. No beeping. Just shuts off shortly into the boot sequence (usually during the .5 seconds the CPU led is lit, sometimes before that particular led lights up). The mobo (Sabertooth 990fx) lights a series of leds in sequence {cpu, ram, gpu, device_boot} to indicate where it is in the boot sequence. If I hold the button down it will cycle on and off repetitively where the step function 'wavelength' is about 0.8 seconds. Doesn't seem too healthy so I avoid that.
- When cold, eventually after pressing the power button multiple times in sequence at 1Hz, the computer will boot. (My theory is that this heats up the PSU enough that no protection mechanism causes the PSU to shut off- due to a failing capacitor perhaps?)
- If I point a space heater at the rear end of the PSU for 3-5 minutes (such that the rear end is warm to the touch [about 75F?]), the PSU will boot without problems on the first try. I don't need to cook the thing, just heat it up to 70-75F or so. I do need to aim the heat directly at the PSU, down lower at the mobo will take much longer. I don't think the heat even needs to dissipate through the whole PSU really. Whatever components that are near the rear are heated up the most, and I think are most likely relevant. For 1.5 weeks this space heater solution has done the trick.
- The PSU has:
- Over Voltage Protection:
- +5V trigger points are 5.5-7.0V
- +3.3V trigger points are 3.76-4.6V
- +12V1 & 12V2 trigger points are 13.4-15.6V
- Under Voltage Protection (power off if line in voltage below 65~75VAC) I'm in the U.S. so I don't think there is a problem here. The manual doesn't specify VDC trigger points.
- Over Load Protection (when the power consumption exceeds 110%~160% of 500W the PSU will shut down in 50ms).
- Short Circuit Protection
- Over Current Protection:
- +3.3V trigger points are 36-55A
- +5V trigger points are 36-48A
- +12V1 & 12V2 trigger points are 25-30A
- Over Temperature Protection (when the heat sink sensor temperature exceeds 90C-100C).
- Over Voltage Protection:
- 3 years ago PSU used to cold boot immediately at colder temperatures- pretty much 35-45F when the boiler in my house went out for a few months during the winter :-)
Related threads (to this PSU model):
- https://www.badcaps.net/forum/showth...ight=elt500awt
- https://www.badcaps.net/forum/showth...ight=elt500awt
- https://www.badcaps.net/forum/showth...ight=elt500awt
Perhaps the heat sink sensor is faulty? There is no documented under temperature protection. Perhaps the cold temperature causes a voltage/current measurement to be out of bounds so the PSU shuts off? I have a cheap multimeter here, but it only updates at 2Hz. Everything appears to be in order once the computer boots. If desired I could go to work and grab some nice 1000+Hz curves depicting various properties of the cold/warm PSU startup. I could also take some photos of the guts of the PSU.
In post#14 of that last thread I pointed to: https://www.badcaps.net/forum/showpo...1&postcount=14 Mad_Professor links to pdfs containing characteristics of components in the PSU plotted against temperature (it seems as temperature decreases, things discharge faster [due to decreasing resistance], and I can't tell how voltage changes as theres a lot of terminology in those that I'm not familiar with). Seems plausible that it is just too cold I suppose. To anyone else who has a PSU that won't startup, try heating it up using a space heater?
Just wondering if anyone had any thoughts or suggestions.
Half of the computer problems is caused by bad contacts 
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